I have a Goodman air handler in the attic. The blower runs continuously after the compressor unit turns off. About 2 weeks ago,I noticed the blower was coming on about a minute after the compressor turned on. Now it won't shut off. I located a relay at the air handler and tapped it with a screw driver handle, but it made no difference. Could this be a bad relay?

Replace the switch. Your screwdriver fix didn't work and could possibly do damage to your system if left in that condition indefinitely. Test the component with a multitester for conductivity.

Relay type... RBM 90-340. For future reference... I measured across the relay contacts (1 and 3) and they were shorted. Replaced the relay and that did the job.